Mikeel's right. If you want some unofficial rules, however, you can look at the first issue of the Online Newsletter: the Inquisitor (which is now the Liber Imperialis for legal reasons).
The first issue is here: http://www.40kterra.com/inquisitor/Issue_1/index.html
Look at the "Alienhunters" article. Which I just happened to write...
__________________ Lord of Fluff and Blood Angels Herald of Nurgle "I wield my power with the Emperor's Authority. Those who would say that I am 'radical' merely have minds too small and impotent to realize all the weapons at their disposal. Do not question my methods on account of these so-called 'Puritans'." -Inquisitor Mathias Rosenadel |